Spinnerette



28, 1951 A. G. DOWSON 2,566,283

SPINNERETTE Filed March 12, 1949 RHODIUM 1- PLATINUM %GOLD INVENTOR.ARTHUR ORDON DOWSON' ATTQENEY Patented Aug. 28, 1951 SPINNERETTE ArthurGordon Dowson, London, England, as signor to Baker & CompanyIncorporated, N ewark, N. J., a corporation of New Jersey ApplicationMarch 12, 1949, Serial No. 81,157

In Great Britain March 16, 1948 i This invention relates to spinnerettessuch as are employed in the production of synthetic fibres and filamentsfor production of rayon, artificial silk, artificial wool and othersimilar materials. Spinnerettes of this character essentially include ajet or nozzle through which the substance or material for extrusion isexpelled under pressure. It is important that the spinner- .ette jetsshould be made of a metallic substance which will resist erosion and anytendency to corrode.

Up to the present it has been proposed to make spinnerette jets fromprecious metal alloys, such for example as gold alloyed with up to 40%platinum; and also platinum alloyed with up to 15% of rhodium. InBritish Patent No. 563,648 there is disclosed an alloy for a spinnerettein which platinum and rhodium are combined with ruthenium. Theseplatinum-rich alloys have been found particularly advantageous ascompared with the known gold-rich gold platinum alloys in that theypossess the highest possible resistance to corrosion and can be producedwith a very fine grain, which enables the holes to be accurately drilledand the walls to be given a very high polish.

It is an object of the present invention to devise a superior preciousmetal alloy for constructing spinnerette jets which will retain all theadvantages of the platinum-rich alloys referred to above but which willhave in addition a very high hardness. This is achieved by employingalloys of platinum with rhodium and gold which are age-hardening, and itis therefore possible to make a sheet of the alloy in a reasonably softcondition to allow mechanical forming of the spinnerette cups anddrilling of the holes. The formed spinnerettes can then be hardened byheat treatment.

In accordance with the present invention, spinnerette jets are made froman alloy of platinum with rhodium and gold, which alloy contains 4 to15% of gold, 5 to of rhodium and the balance of platinum, theproportions being so selected that for gold contents less than 5% theminimum rhodium content is increased above 5% by an amount equal to fivetimes the amount by which the gold content is below 5%. Thus with a goldcontent of 4.5% the rhodium must be not less than 7.5 and with 4% goldthe rhodium must be not less than 10%. When both rhodium and gold arepresent in quantities approaching the stated maxima the hardness oi theallow in the softest condition is increased so that the forming anddrilling operations become difficult.

seams. (01. 18 -8),

For practical purposes the total gold and rhodium content preferablyshould not exceed about 25%. Whereas with the previously knownplatinumrich alloys it was not feasible to produce jets having afinished hardness greater than about 200 .V. P. N., jets made accordingto the present invention can be produced with a hardness of 400 V. P. N.or even higher.

The above alloys are shown in the drawing which represents a graph ordiagram thereof.

To show how the invention may be carried into effect several exampleswill now be given.

Example I In this example, an alloy is prepared containing:

% platinum '7 rhodium 7 Vs gold The alloy is produced in sheet form andis treated by raising it to a temperature of about 1050 C. to1100 C.-for 15 minutes. It is then quenched in cold water and is thereaftermechanically formed by the production of the cup and the drillingthereof. The formed jet is then heated for l to 2 hours at a temperatureof 620 to 650 C. and allowed to cool. The finished jet has a hardness of350 to 400 V. P. N or better.

Example II In this example, an alloy is prepared contain- 1118:

85% platinum 5% gold 10% rhodium The process of producing the finishedjet is substantially the same as in Example I and the hardness of thefinished jet is about 450 V. P. N.

Example 17V In this example the proportions of the constituents of analloy are chosen to be the same as those of Example I except that 20% ofthe platinum is replaced by palladium, the replacement being made atomfor atom. It will of course be understood that the expresison "atom foratom is used to mean that 20% of the platinum is excluded and an amountof palladium containing an equivalent number of atoms is substituted.The weight of the palladium will thus be less than that of the platinumwhich it replaces. The alloy prepared in this way is processed in themanner described in Example I and the hardness of the finished jet willbe of the order of 250 to 300 V. P. N.

It will be realised from cons deration of Example IV that it is possibleto substitute under certain circumstances a certain amount of platinumby palladium. The alloy produced does not necessarily give as goodresults as those in which there is not substitution of platinumconstituent but as will be appreciated it is often possible tosubstitute in a platinum-rich alloy a proportion of palladium withoutsignificantly altering the final desired properties of the alloy.

The proportions of the constituents of the alloys that may be used inthe fulfilment of the invention are illustrated by reference to the.accompanying diagram. The diagram represents the conventional diagramfor a ternary alloy. The horizontally hatched. portion includes withinit those points which define the desired ratio of proportion between thethree constituents. From the diagram it can be seen that as the goldconstituent is reduced from to 4% the corresponding range for rhodiumincreases. Thus for an increment of reduction in the gold as between 5%and 4%, the minimum rhodium content increases by an increment that isfive times as great as the first mentioned increment, thereby ensuringthat when the gold constituent is reduced to 4% the minimum rhodiumconstituent has been increased to V I claim: v n V 1. A spinnerette ofan alloy of platinum with rhodium and gold, which alloy contains 4 to ofgold, 5 to 15% of rhodium and the balance of platinum, the proportionsbeing so selected that for gold contents less than 5% the minimumrhodium content is increased above 5% by an 4 amount equal to five timesthe amount by which the gold content is below 5%.

2. A spinnerette as claimed in claim 1 wherein said alloy has a maximumaggregate amount of gold and rhodium equal to 25%.

3. A spinnerette as claimed in claim 2 wherein the alloy isage-hardened, said age-hardening being carried out after the spinnerettehas been formed.

4. A spinnerette as claimed in claim 3 wherein the spinnerette is formedfrom a sheet of the alloy after the latter has been heat treated forapproximately 15 minutes at 1050 to 1100 C. and quenched, the formedspinnerette being then heated for 1 to 2 hours at 620 to 650 C. andallowed to cool.

5. A spinnerette as set forth in claim 1 wherein the platinum content isreplaced to anextent of not more than 20% by an atom for atom quantityof palladium.

. ARTHUR GORDON DOWSON.

REFERENCES CITED" The following references are of record in the file ofthis patent:

UNITED STATES PATENTS OTHER REFERENCES Rhodes, treatise in MetalIndustry, May ll, 1945, pages 290, 291.

1. A SPINNERETTE OF AN ALLOY OF PLATINUM WITH RHODIUM AND GOLD, WHICHALLOY CONTAINS 4 TO 15% OF GOLD, 5 TO 15% OF RHODIUM AND THE BALANCE OFPLATINUM, THE PROPORTIONS BEING SO SELECTED THAT FOR GOLD CONTENTS LESSTHAN 50% THE MINIUM RHODIUM CONTENT IS INCREASED ABOVE 5% BY AN AMOUNTEQUAL TO FIVE TIMES THE AMOUNT BY WHICH THE GOLD CONTENT IS BELOW 5%.